A fair few aircraft have an aileron rudder interconnect (ARI) usually as part of a stability augmentation system (SAS); the F-15 definitely does, some research aircraft (M2F2) had a configurable version of ARI where you can set the gain via a cockpit control. The gain on the F-15 is a function of elevator and flaps (at elevator -24 the gain is -0.9, 0 is -0.105, 15 is 0.406); flaps adds roughly 0.1 to these figures. The F-15 has also got a yaw damper - but this is part of the SAS and can be turned off. You can notice that the yaw damper is off often at M>0.8 where you can get yaw oscillation (it's a feature of the airframe).
The built auto coordination is a very simplistic ARI - it's not a yaw damper.
All of the Boeing 7xx series have a yaw damper; since 1959 when they fitted it to the 707; pretty certain that all of the Airbus have it as well.
It's fairly easy to add an effective yaw damper as it's really just a function on the angular velocity
r ; this is the F-15 version.
Code: Select all
<scheduled_gain name="fcs/yaw-damper-sum">
<input>velocities/r-aero-rad_sec</input>
<table>
<independentVar>velocities/vc-kts</independentVar>
<tableData>
0 0
80 0
120 3.6251
650 1.65
890 1.00
1000 0.5
</tableData>
</table>
<clipto>
<min>-0.2000</min>
<max>0.2000</max>
</clipto>
</scheduled_gain>
<scheduled_gain name="fcs/yaw-damper-dmd">
<input>fcs/yaw-damper-sum</input>
<table>
<independentVar>aero/qbar-psf</independentVar>
<tableData>
2.9900 0.0000
3.0000 1.0000
</tableData>
</table>
<gain>fcs/yaw-damper-active</gain>
</scheduled_gain>
<summer name="Rudder Sum">
<input>fcs/rudder-command-sum</input>
<input>fcs/yaw-damper-dmd</input>
<clipto>
<min> -1.1 </min>
<max> 1.1 </max>
</clipto>
</summer>